Recently, as nano and bio technologies have been developed, it is important to measure thermal properties of a minute volume of a sample. In addition, since a material used for the nano and bio technologies is expensive, an amount of the material needed for measuring the thermal properties thereof is an important factor.
An ideal method of measuring thermal properties of an object having a minute volume employs point heating and point sensing techniques.
A conventional measuring apparatus that employs the point heating and point sensing techniques includes a Peltier vacuum gauge (see Korean Patent No. 0407815). The Peltier vacuum gauge measures a thermal conductivity coefficient of the periphery of a point temperature sensor using only one point temperature sensor and measures a degree of a vacuum from the thermal conductivity coefficient.
However, when the point heating is performed by using the Peltier effect, since heating and measuring techniques are based on the same theory such as a thermoelectric effect, heating and measuring circuits electrically interfere with each other. Accordingly, an additional circuit for distinguishing measured signals with respect to time is necessary.
In addition, it is impossible to measure the thermal properties in real time by extracting a temperature signal while heating a tip of the point temperature sensor by an alternating current source.